People have the wrong ideas about knives. A knife doesn’t cut like a razor or a plane iron on the push stroke. It’s somewhat like a saw with teeth that cuts in a sliding motion as it’s pushed or pulled. A properly sharpened knife is honed to a fine edge, yet has an appropriate roughness so that it has bite, or an ability to sink into the cut.
Understanding the subtleties of sharpening is what we’re about at Bernal Cutlery, in the Mission District of San Francisco. We’ve sharpened thousands of knives. We also sell knives and teach people how to sharpen anything from a kitchen knife to a meat cleaver. We’ve learned there’s more to sharpening than a fine edge.
Sharpening takes into account whether the knife is Japanese or Western, its material (stainless or carbon steel), and how the knife is used (slicing meat or fish, chopping vegetables, paring). The user’s preferences must be considered. We also think sharpening is fun, and one of the best parts of my job is talking to the amateur and professional knife users that we serve.
We sharpen all our knives by wet grinding, typically finishing by hand on Japanese water stones. How fine we hone the knife depends on the knife and sometimes the user’s preferences. To sharpen a knife, you need a basic but comprehensive set of water stones. In the Japanese grit numbering system, coarse stones are 220 to 600 grit, medium stones are 800 to 1,200 grit, fine stones are 4,000 to 8,000 grit. These stones and a strop might cost as much as $150, but you’ll get many years of use out of them, and there are inexpensive alternatives.
“I like the Japanese knives, I like French knives. Whatever’s sharp,” Wolfgang Puck once said in an interview.
Knives are essential tools in every kitchen, but what do you do when yours start to lose their edges? We checked in with chefs and experts for their knife sharpening tips—from easy-DIY tips to more professional methods.
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For how much we spend on kitchen gadgets, from dehydrators to air fryers, sous vide wands and blenders with the horsepower of a small automobile, comparatively little attention is often paid to a cornerstone of cooking: knife maintenance. It’s unfortunately too common to walk into someone’s home and see top-shelf knives from powerhouse brands like Global or Zwilling, with edges equivalent to butter knives.
Thankfully, it’s not hard to give your home cutlery a touch-up. These are some of our favorite tools to keep knives sharp, spanning a cross-section of convenience and utility.
First, you need a honing steel
Most people confuse a honing steel with a sharpener. A honing steel (pictured below) is for everyday use. It’s a ridged metal wand that you run your knife across. You’ve probably seen flashy cooking show contestants dramatically swiping them through the air like swashbucklers with swords.
While a honing steel does help a knife slice better, it doesn’t actually sharpen a knife. Here’s how it works: When your knife cuts food and slams into a hard cutting board, its microscopic teeth get out of alignment, and a honing steel straightens and smooths them, giving you the feeling that your knife is sharp. If you cook every day, you should hone your knife at least once a week, but you can do it every time you cook if you prefer. Be sure to replace your honing steel once it starts to wear down.
Hone your knife
When your knife’s blade has taken a beating and needs more help, it’s time to step things up and get out the sharpener, which should only be used a handful of times a year.
Electric sharpeners may seem like the superior choice, but they’re probably the worst tool for sharpening a knife. I learned this in culinary school, when a fellow student pulled one from his tool kit and our French chef instructor swiftly swatted it across the kitchen. Electric sharpeners strip too much metal from the knife, destroying the blade and weakening it over time. (Which is a shame if you spent a lot of money on your beloved knives.)
Handheld sharpeners are OK, but they’re not the best.
What you really want is a whetstone (also known as a sharpening stone or water stone), which is the preferred tool for sharpening knives because it gives you, the cook, complete control. Sharpening stones are basically long, rectangular blocks of composite stone, typically with a coarse grit on one side and a fine grit on the other. As seen below, the side with the lower number is used for sharpening, and the side with the higher number is used for polishing:
Save yourself a lot of heartache and bloodied fingers and order one of these whetstones right now. It’s cheap, low maintenance and will make a huge difference when you’re chopping onions.
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For those who prefer a DIY approach to knife sharpening, Claudia Sidoti, head chef at HelloFresh, has a few ideas to share, the first of which is using a piece of sandpaper: “The best size will depend on the knife and how much you want to sharpen it,” Sidoti says. She suggests starting with a coarser sandpaper and working your way up to a finer piece for maximum sharpness. Another of her methods is using a nail file, running the cutting edge of the knife blade against it.
- Honeycomb Design Diamond Whetstone Grindstone Tool
- Double Sided Diafold Sharpener Fine
How to Sharpen a Knife With a Whetstone
One of the ways to sharpen a knife is with a whetstone. Using a whetstone may take a bit of practice, but once you get the hang of it, you’ll be able to keep knives razor-sharp while saving time and money. One important note: “Whet” doesn’t mean “wet”—it means sharpen, although some whetstones require soaking. Check your manufacturer’s instructions.
To begin, get a two-sided whetstone, with a coarse grit on one side and a fine grit on the other. Different knives require the edge of the knife to be applied to the stone at a different angle, depending on the manufacturing specifications. In general, it’s somewhere around 22 degrees. To visualize this, picture 90 degrees, which is straight up and down. Then imagine half of that, which is 45 degrees.
And then another half of that is 22 1/2 degrees. (Don’t worry about the half degree.) Consult the technical info that came with your knife or check with the manufacturer to verify the correct angle you should be using.
- Place the whetstone on a cutting board or countertop with the coarse grit face up. Place a wet paper towel or kitchen towel underneath the stone to help keep it from sliding.
- With one hand, grasp the knife by the handle and hold the edge of the knife against the stone, point-first, with the cutting edge meeting the stone at around a 22-degree angle. You can stabilize the blade with your other hand.
- With moderate pressure, slide the blade forward and across the whetstone, covering the entire length of the blade and keeping the blade flush against the stone at a constant 22-degree angle.
- Do this 10 times, then flip the knife over and give the other side of the blade 10 strokes on the whetstone.
- Flip the whetstone over to the fine grit side and give each side of the blade 10 strokes.
- Finish by using a sharpening steel to hone the blade, then rinse and wipe the blade dry to remove any metal particles.
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- Always sharpen in the same direction, whether it’s front to back or back to front.
- Don’t believe the hype about knives that supposedly “never need sharpening.” Cutting produces friction, and friction causes a knife’s edge to lose its sharpness. There’s no avoiding the laws of physics.
- Don’t attempt to sharpen ceramic knives; they are brittle and prone to breaking.
- Take care of your knife so it retains its edge longer. Store your knife so it is not resting on its edge, and protect the edge with a blade protector if you keep it in a drawer. Hand-wash the knife immediately after each use and only store it when it is dry.